788 FXUS65 KVEF 020056 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 556 PM PDT Sun Jun 1 2025 .SYNOPSIS...Showers and thunderstorms are expected across much of the forecast area through Tuesday as low pressure pulls remnant tropical moisture into the region. The greatest rainfall amounts will likely be in northwestern Arizona tonight into tomorrow. Cooler temperatures can also be expected areawide before they begin to climb again midweek. && .UPDATE...Mesoanalysis this evening shows two very different areas. The first is the scattered showers and thunderstorms that developed in the Southern Great Basin and northern Inyo County this afternoon. This is where there was ample sunshine to allow for weak destabilization along with weak upper level diffluence. At the surface though, moisture was lacking as PWATs remains around 0.50in and surface RH was dry. Very little rain was reported with activity in this area, tough recent webcam images in northern Lincoln COunty do suggest some saturation and rain reaching the ground. Instead gusty winds were the main impact as surface dry air resulted in gusty outflow winds. Gusts of 30-40 MPH were reported under some of these storms, especially in Inyo County where instability was highest. As the sunset and instability wanes in this region, so should the precipitation. Updated the evening and overnight forecast to reflect this trend, with most of the shower and thunderstorms ending by 11PM tonight. Further south, satellite imagery showed a circulation off the southern California Coast slowly moving northeast. Ample moisture was advecting from this feature- PWATs and dewpoints increased in San Bernardino, Clark, and Mohave counties on moist 850mb flow. Despite this moisture, very little was able to develop precipitation wise. The better forcing remained south and east of our local area so the best development was closer to this area. Any areas of rain that could make it this far north quickly dissipated likely due to upper level convergence. With significant cloud cover in place through the afternoon, destabilization was hindered which added to the lack of support for precipitation locally. Light rain was reported in a few spots of southern MOhave County, otherwise its been dry. The upper levels system is expected to lift northeast in Arizona overnight, which should give us a shot of some rain. The best chances will be in southern Mohave County where the best moisture and forcing will exit. Some models show better development after midnight with moderate to briefly heavy rain south of I-40 in Mohave County and eastern San Bernardino County, which matches up well with higher probabilities for 0.10 or more rainfall through the nights but also where RAP has instability developing overnight. This would also be the area where a current uptick in radar returns south of Blythe should shift into later tonight (something to keep an eye on for later). Further north and west in Clark and northern Mohave counties- models are uncertainty how to handle the overall set up and have varying solutions on what is able to develop. Kept a slight chance for rain southern Clark and northern Mohave through 5 AM, but low confidence in if this will occur. In addition to the precipitation, gusty south to southwest winds developed across the region as the low shifted closer to the area. Widespread gusts of 25-35 MPH were reported today, with higher gusts up to 40 MPH reported in eastern Clark through the Colorado River Valley and Mohave Counties. These winds will persist another few hours then diminish through the night. The highest winds should be the next few hours in the Colorado River Valley. Low temperatures tonight will be mild due to the amount of cloud cover, but will still cooler than last night as heights fall and a cooler airmass moves into the region. -Nickerson- && .PREVIOUS DISCUSSION...300 PM PDT Sun Jun 1 2025. .SHORT TERM...through Tuesday. Upper low currently spinning off the southern CA coast will continue to help draw remnant moisture northward from tropical storm Alvin. Dew points continue to increase across the southern half of the forecast area with most areas seeing readings in the 40s and 50s. This moisture will continue to increase into this evening as the upper low slowly starts to push east. So far, the main thunderstorm activity has been across Lincoln, central Nye, Esmeralda, and northern Inyo counties where there has been some low level moisture increase along with more intense heating. Increasing mid-level lapse rates along with CAPE values around 250-500 J/kg will continue to favor those areas through the afternoon for additional thunderstorm development. Although there could be some brief heavy rain, the flash flood threat remains low, but gusty winds are certainly possible. Areas over the southern portions of the CWA where the moisture is deeper have been slow to produce anything other than some light showers or virga as the area remain fairly stable at this time due to the overall cloud cover; however, as we go later into the afternoon and especially this evening we should see the CIN start to erode with an increase in overall instability allowing for isolated to scattered thunderstorms to develop. These will mainly be focused across southern Clark, eastern San Bernardino, and southern Mohave counties. With PWs about 250-300 percent of normal, isolated areas of flash flooding is not out of the question. Another concern will be the increasing southerly winds this afternoon and evening. An increasing surface pressure gradient ahead of the low will create some gusty south winds with a few areas seeing gusts over 40 mph. This isn`t expected to be widespread, but could affect Lake Mead, Lake Mohave, and the Colorado River Valley. This will have the greatest impact on the area lakes and lower the Colorado River with boaters needing to take some extra precautions. As the low continues to approach the southern portions of the area, we will see showers and thunderstorms persist overnight especially south and east of I-15 with areas of central and southern Mohave County along with the lower Colorado River being the more favored areas. Due to the amount of available moisture, some of stronger storms could produce areas of flooding. Going into Monday, the aforementioned area of low pressure will be over central Arizona as another low drops down the California coast. Very little of the moisture from Alvin will be scoured out of the area and with stronger heating and increased instability we will see another day of scattered showers and thunderstorms. Most of these storms will remain over the higher terrain, but a few valley locations could also see a few thunderstorms. This pattern will persist through Wednesday with daily afternoon, mainly higher elevation thunderstorms. .LONG TERM...Wednesday through Sunday. A northwest flow will set up over the region mid-to-late week. Along this northwest flow, a series of shortwaves will glide down into the southern Great Basin and Mojave Desert. With no mechanism to shove remnant moisture out of the forecast area from the early- week systems, these shortwaves will tap into the leftover moisture, resulting in at least slight PoPs existing through Thursday. Best chances will exist in the southeastern Great Basin and eastern Mojave Desert on Wednesday and Thursday with breezy south-southwest winds elsewhere (20-30 mph). Despite these shortwaves, a growing ridge of high pressure over the eastern Pacific as well as over northern Mexico will result in increased 500 mb heights across the Desert Southwest. As such, temperatures will continue to climb back to 4 to 6 degrees above seasonal normals heading into the weekend, with temperatures approaching 10 degrees above-normal heading into the next work week. This will result in desert valleys reading high temperatures in the 100s once again, with widespread "Moderate" HeatRisk. && .AVIATION...For Harry Reid...For the 00Z Forecast Package...South winds with an occasional push of southeast winds persist into the afternoon with gusts 20 to 25 knots. Overnight, chances for showers and thunderstorms will increase after 07z, but confidence remains low that they will impact the terminal. Showers and storms are more likely east and south of Las Vegas with CIGS dropping as low as 7k feet at times. The main threat from any storms will be erratic gusty winds. Chances for showers and thunderstorms will decrease, but not go away entirely, early Monday morning. For the rest of southern Nevada, northwest Arizona and southeast California...For the 00z Forecast Package...South to southwest winds gusting 20 to 30 knots will be common across the region into this evening. Chances for showers and thunderstorms persist into the evening across northern Inyo, Esmeralda, central Nye, and Lincoln counties. We will need to watch for the potential of showers and isolated thunderstorms developing overnight and pushing up the lower Colorado River and into the Las Vegas Valley after 09z. Confidence remains low in this scenario. Isolated showers and thunderstorms will remain in the forecast Monday afternoon. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ SHORT TERM...Gorelow LONG TERM...Soulat AVIATION...Gorelow For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter